1. Field of the Invention
The invention is a perpendicular recording head for use with magnetic storage media. The perpendicular recording head has an unusually thin main pole for concentrating the magnetic flux over a smaller portion of the magnetic storage medium's surface area than current perpendicular recording heads.
2. Description of the Related Art
Although other perpendicular recording heads have been developed, the present invention improves upon presently known perpendicular recording heads by utilizing a main pole made by plating a magnetically permeable material over a nonmagnetic substrate, thereby permitting an unusually thin main pole to be produced.
An example of a magnetic recording head is described in U.S. Pat. No. 4,078,300, issued to J. P. Lazzari on Mar. 14, 1978. This patent describes a method of making a magnetic recording head intended to work in conjunction with a track of a magnetic storage medium having a narrow width. The method involves removing material from the edges of the pole tip to reduce the surface area of the main pole's bottom surface.
U.S. Pat. No. 4,138,702, issued to J. G. Magnenet on Feb. 6, 1979, describes a head arrangement for perpendicular recording on a magnetic record carrier. The head arrangement has an electromagnet with a core and a magnetic shunt on opposite sides of the magnetic recording medium.
U.S. Pat. No. 4,546,398, issued to J. Toda et al. on Oct. 8, 1985, describes a perpendicular recording head. The perpendicular recording head includes a main pole made from a thin magnetic film, and a spiral coil electromagnetically coupled to the main pole.
U.S. Pat. No. 4,652,956, issued to H. Schewe on Mar. 24, 1987, describes a recording head for perpendicular magnetization. The recording head has a pair of magnetic legs forming a ring-shaped member, and separate read and write wire coils. The read coil is located between the two magnetic legs, and the write coil is located outside one of the two magnetic legs.
U.S. Pat. No. 4,731,157, issued to J. P. Lazzari on Mar. 15, 1988, describes a process for making a perpendicular recording head. The process includes the steps of depositing magnetic film on an insulating substrate, etching a channel in the magnetic film for containing a coil within a dielectric material, etching another channel in the dielectric layer for containing a second magnetic film, removing dielectric material to expose the lateral edge of the second magnetic film, and depositing additional dielectric material on top of the second magnetic film.
U.S. Pat. No. 4,943,882, issued to T. Wada et al. on Jul. 24, 1990, describes a perpendicular recording head. The recording head includes a first main pole surrounded by a conductor coil, with an insulator covering the first main pole and coil. The first main pole is in contact with a magnetic substrate at its top end. A second main pole is in contact with the first main pole. This assembly is covered with a protective overcoat. A similar recording head is described in U.S. Pat. No. 5,225,953, also issued to T. Wada et al. on Jul. 6, 1993.
U.S. Pat. No. 4,974,110, issued to M. Kanamine et al. on Nov. 27, 1990, describes a perpendicular recording head having a main magnetic pole, a spiral coil surrounding the main pole, and a pair of auxiliary magnetic poles on either side of the main pole. The magnetic flux from the resulting two magnetic leakage paths and the coil cancel each other out, thereby reducing edge noise.
U.S. Pat. No. 4,985,792, issued to M. B. Boir on Jan. 15, 1991, and assigned to the assignee of the present inventors, describes an improved spindle motor for a fixed disk drive for a computer.
U.S. Pat. No. 5,073,836, issued to H. S. Gill et al. on Dec. 17, 1991, describes a perpendicular recording head. The primary magnetic pole is separated from the auxiliary pole by a distance sufficient to increase the reluctance of the recording head, thereby minimizing erasure of data within the recording medium.
U.S. Pat. No. 5,241,430, issued to D. W. Janz on Aug. 31, 1993, and assigned to the assignee of the present inventors, describes a disk drive which accepts write operations during manufacture, but only accepts read operations in use. The drive's controller responds to power supply voltage levels available to the user's computer by performing only read operations, but will perform a write operation in response to a higher voltage.
U.S. Pat. No. 5,430,589, issued to M. B. Moir et al. on Jul. 4, 1995, and assigned to the assignee of the present inventors, describes a disk drive having a vibration-absorbing insulator between the housing and the shaft for the storage disks.
U.S. Pat. No. 5,796,557, issued to G. N. Bagnell et al. on Aug. 18, 1998, and assigned to the assignee of the present inventors, describes a disk drive including six storage disks and fitting within a 3.5 inch, half height port.
U.S. Pat. No. 5,996,045, issued to L. Lee et al. on Nov. 30, 1999, and assigned to the assignee of the present inventors, describes a disk drive arrangement combining a master drive and a slave drive. Both drives use the same IDE bus. The host computer is able to send commands over the IDS bus in the same manner as if only one disk drive was present, and the command is then carried out by the appropriate drive.
The article, Sakhrat K. Khizroev, James A. Bain, and Mark H. Kryder, “Considerations in the design of Probe Heads for 100 Gbit/in2 Recording Density,” IEEE Transactions on Magnetics (September 1997) pp. 2893-2895, describes work performed by two inventors of the present invention towards development of giant magnetoresistive read heads capable of reading magnetic storage media having high storage densities.
The article, Jon William Toigo, “Avoiding a Data Crunch,” Scientific American (May 2000) pp. 58-74, describes several approaches to increasing the information storage density within fixed computer drives.
None of the above described patents and publications describes a perpendicular recording head for use with magnetic recording media having a main pole formed by plating a nonmagnetic substrate with a magnetic surface covering. Additionally, none of the above patents and publications describes a recording head having the advantages provided by the present invention.